Shock-absorbing device for vehicles.



L. C. WELCH.

PATBNTBD PEB. z5, 1908.

SHOCK ABSCRBING DEVICE POR VEHICLES.

APPLICATION FILED AUG. 9, 1907.

Wit" use@ am i Wolf/,

i Maine, have invented cient in use, and composed of few parts.

2-5 by the piston/.can be freely moved in one di- UNITED PATENT OFFICE;

n .LEWIS C. WELCH, OF' OAKLAND, MAIN. SHQCK-ABSO-RBING DEVICE 'FOB VEHICLES.

i To all whom fitjmay concern: l

Beit known that I, LEWIS C. WELCH, a

' citizen of the United States, residing at Oakland, in the county of Kennebec an State of plrovements in Shock-Absorbing Devices'fo-r ehicles, ,of which the following is a specification.

This invention relates toshock absorbing devices .intended for self-propelled or other vehicles, whereby the disagreeable jolting of the vehicle body when assin over` inequalities in the ,roadbed w' l be e out, however, destroying the resiliency of the body supporting springs.' p

improve and simplify the construction and operation of devices of this characterso as to be comparatively easy and I inexpensive to manufacture, thoroughly reliable and effl- A further object of the inyention'- is ,the rovision of a s ock absorberlcomprisin a ydraulic cylinder containin a piston which is`provided with valve contro led vports whererection while retarded in the other, there being by-passes in the wall of the 'cylinder for permitting liquid to pass by the iston' durin the movement for checking t e recoil o? the body supporting springs.

A further object of the invention is the provision of a shock absorber of the type -referred to that is pro-vided with a hollow piston rod containing a floating piston on one side of kwhich is an air cushionthat serves to cushion the shocks and insure easy movement.

With these objects in view and others, as will appear as the description proceeds, the invention comprises the various novel features of construction and arrangement of arts whichwill be more fully described hereinafter and set forth with particularity in the claims appended hereto.

In the accompanying drawing, which i illustrates one of the embodiments of the invention, Fi re 1A is a vertical longitudinal section of t e shock absorber showing the parts in the position occupied when the body supporting springs of the vehicle are compressed. elevation of the device showing the parts in the position'occupied during the re-coil er expansion of the body supporti springs. Fig. 3 is a transverse section on. 'ne 3 3,

Specification of Letters Patent. 'Appnqmgn ma iugm s. 1907. smalto. estesa new and useful Im.

inated. with- The invention has for one of its objeatsto- Fig. 2 4is a partial section in side.

. Patented Feb. 25, 190.8.

I Fig. 1. Fig. 4 is a plan view of the valves controlling the ports of the piston.

Similar reference characters are employed to designate corresponding parts throughout the several views. q

, Referring to the drawing, 1 designates the cylinder .of the device that is internally bored, and on the lower end thereof is threaded a cap 2 for closing the same, and the opposite end of 'the cylinder is provided with a stuffing box 3 that contains a packing 4 that is compressed by a gland 5, there being'a ca nut 6 or pressing the gland inwardly. In t e cylv inder is a piston designated generally by 7 that is formed on a rod 8 which passes outwardly through the stuffing box. The pistonconsists of an upper flange 9 that has a working fit with the cylinder and is provided. with a plurality of ports 1 0 for permitting oil or other liquid to pass from one side of the piston to the other. Spaced from the flange 9 is a secondflange 11 that is of smaller diameter than the cylinder so as to form an annular space for permitting the liquid to pass, and this space is of the same area asthe combined areas of the ports 10, the top side'of the flange 11 forming a seat for an annular valve 12. The top side of the valve `12 is formed with a ridge 13 which contacts with the bottom side of the flange 9 when the valve is fully open and byA this construction, the valve will not adhere to the said. fiange, but freely close under the'upwardmovement of the piston. The movement of the valveis comparatively small so that it is extremely sensitive to changes in movement of the piston, thereby causing a rapid action. In the internal surface of the cylinder 1 are vertically extending ta ering grooves 14 which are of different lengt s and taper in an upward direction and these grooves form by-passes around the piston which cause a varying resistance to the flow of liquid around the piston when thevalve 12 is seated. The piston rod 8 is hollow for a ysuitable length and open at its lower end,

and having a working fit in this bore 15 is a floating iston 16 that is retained in the iston rod y a cross bar 17 at the open en of the bore, the space on the upper side of the piston forming an air pocket or cushion,

,while the bore at the under side of the piston is in free communication with the cylinder.

The piston rod is of suitable length and at its free `endis a spherical enlargement or ball l18 that is preferably threaded thereon and Y retained in position by a pin 19 passing through the ball and envagin .in agroove 1n the end of the piston ro T 1e lower end of the device is )rovided with a spherical enlargement or all 20 that is formed on ythe cap 2. 'lhese enlargements are adapted to engage in socketed members attached respectively to the seats for the body s rings or other suitable part of the vehicle t iat is fixed with respect to the axle and to the vehicle body so that the relative movement of the running gears and body will bring the shock absorbing device into play, and these ball and socket joints permit of relative oscillating movement between the running gears and body in a horizontal direction both longitudinallyY and transversely.

ln practice, after the cylinder has been filled with oil or any other suitable hydraulic medium through the normally plugged fillin opening 21 in the cap 2 the device is ap lie to the vehicle so that the cap end thereo will be lowermost. When an obstruction in the roadway is met, the body supportingsprings are vcompressed and the piston is forced downwardly in the cylinder 1, thereby causing the liquid on the bottom side of the pisi ton to ralse the valve 12 and permit the liquid to move to the top side of the piston. The air cushion above the piston 16 permits more oil to enter the hollow of the piston rod to compensate for the oil displaced by the piston rod as it is moved into the cylinder. The air cushion imparts resiliency to the downward movement and by compensating for the displaced oil, it reduces the inward pressure so that there Will be no shocks trans-f mitted through the device. During the recoil of the body supporting springs, the movement is checked solely by the hydraulic me ans which thus insures a uniform actiony at all times. The re-coil is checked with decreasing speed to allow, as far as practicable, the drop of the axle as an obstruction is passed over and also to prevent the holding of the body supporting springs compressed too long which would be objectionablefor the reason that severe jolting would be' caused in case two or more obstructions in the road were passed over in quick succession. During the re-coil movement, the valve 12 will be immediately seated and the.oil on the top side of theA piston and in the hollow of the piston rod will. pass to the bottom side of the piston as indicated by the arrows in Fig. 2,.the freedom of the passage of 'the liquid oil be# coming less and less toward the upper limit of the movement of the piston, since the bypass grooves 14 become more and more restricted.

In case of a very sudden compression of the body supporting springs, as in passing over obstructions at a high rate of speed, the resistance of the device will not be materially increased owing to the fact that the movevsition ofthe piston c anges, and a ment of the piston will cause more oil to be displaced than can pass throu h the piston orts, and this oil thus disp aced will be orced into the bore of the. rod and against the air cushion, while a momentary vacuum will be produced above the'piston. Bythe compression of the body sup orting springsv ata moderate rate of speed, t e resistance of thedevi'ce will not be materially increased since the slightly increasing internal pressulr) due to the air being compressed by the o1 r it enters the cylinder, will be offset by the increasing number and size of the tapering Uroovesin the wall of the cylinder, thereby lessening the resistance below the piston.

In a construction ofi` the character referred to,` the valve. arrangement is compact and the action positive and comparatively little motion of the piston or cylinder is re uired the displacement of the piston rod 'as to open or close the valve, thereby ren ering the device sensitive so thatlfailure to operate lis avoided.' Furthermore, the device is composed of few parts of simple construction and so designed that the liability to derangement is reducedto a minimum.

From the foregoing description, taken in connection with the accompanying drawing, the advantages of the construction and of the method of operation will be readily apparent t'o those skilled in the art to which the invention appertains, and while I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, I desire to have it understood that the apparatus shown is merely illustrated and that such changes may be made when desired,'as are within the scope of the claims. Having thus described the invention, what I claim is- 1. In a shock absorber for vehicles, the combination of a cylinder, a piston therein, by-passes extending from one side to the other of the piston and designed to vary the resistance to the passa e ofliquid as the poneum-atic cushioning device associated wit the piston for assisting' in absorbing the shocks.

2. In a shock absorbing device for vehicles, the combinationbf a cylinder provided with longitudinally extending grooves of diminishing cross section from one end to the other, a piston in the cylinder.- adapted to move back and forth in thegrooved portion of the cylinder, ports in the piston, a valve arranged to permit a free flow of liquid through the ports when the piston moves .in one direction and positively interruptsthe flow when the piston moves in the opposite direction, and a pneumatic cushioning devlce associated with the piston for assisting with longitudinally extending grooves of diminis ingl cross section from one end toward the ot er, a piston in the cylinder adapted to move back and forth in the grooved portion of the cylinder, ports-in the piston, a valve arranged to permit a free flow of liquid through the ports when the piston moves in one direction and' positively interrupts the flow` when the iston moves in the opposite direction, a ho low piston rod communicating with .the cylinder, and pneumatic cushionin means in the rod.

f1. In a shock absorbing device for vehicles, the combination of a cylinder, a piston therein provided with spaced flanges o f different diameters, the flange of larger diaineter having a working fitvwith the cylinder, and ports in the said larger flange, a valve arranged to close the s ace between the smaller flange and cylin er as the piston moves in one direction, and a plurality of bypasses of different lengths and resistances connecting points onf o posite sides of the piston.

5. In a shocli a sorbing device for vehicles, the combination of a cylinder, a piston therein comprising a pair of spaced anges of different diameters and arranged in fixed relation, the flangeiof larger diameter having contact with the cylinder, ports in the lar er flange, and an annular valve dis osed etween the flanges for interrupting t e flow of liquid through the ports when the piston -moves in one direction, said valve being bodily removable and retained betweenthe flanges and carried back and forth with the piston by the flanges.

6. In a shock absorbing device for vehicles, the combination of a `cylinder, a piston therein comprising a pair of spaced flanges of different diameters, the flange of larfrer diameter having contact with the cylinder, ports in the larger flange, an annular valve adapted to seat on the flange of smaller diameter for closing the space between the periphery of the latter and internal surface of vthe cylinder, said valve being free to move between the two flanges.

7 In a shock absorbing device for vehicles, the combination yof a cylinder, a piston f hollow of the cap, an

therein provided witli's aced flanges of different diameters, ports in the larger flan e, an annular valve disposed between t e flanges and adapted to be seated and unseated by the inltial art of each stroke of the piston for controlling the flow through theports, a hollow piston rod connected with the piston and communicating with the cylinder, and a floating piston in the rod and confining a body of elastic fluid in the latter.

8. In a shock absorbing device, the combination of a cylinder provided with longfitudinally extending internal grooves of di erent lengths tapering in the saine direction, a pis'- ton comprising a pair of spaced flanges of dif.- ferent diameters and having a flange of larger diaineter'in contact with the cylinder, an annular valve dis osed between the flanges and of an external iameter equal to the internal diameter of the cylinder, a hollow piston rod extending into the cylinder and closed at one end and having its open end commiinicating with the cylinder, a floating valve in the rod and confining a body of elastic fluid therein, `and a stop at the open end of the rod for retaining the floating-'piston therein. v l

9.l In a shock absorbing device for vehilcles, the combination of a cylinder o en at one end and provided with a head at t e o posite end havin an opening, a piston in t e cylinder inserte and removed through the open end of the latter, a piston rod integrallg,T connected with the piston and extendin through the opening in the head of the cy inderand removable through the o en end of the latter, a 'stuffing box on the eaded end of the cylinder forA the piston rod, a cap for the olpen end of the cylinder, a ball on the free end of the iston rod to permit the rod to be inserted t ough the stuffing-box.

` I n testimony whereof I afHx my signature in presence .of two witnesses.

LEWIS c. WELCH.y

Witnesses: v

FRED' HALLETT, FRANK S. GARLAND.

a ball removably mounted on the 

